Yup. That never seems to be a problem. It's kinda tough to artificially force things to a one monster per one page layout when there's so much more to cover with some monsters than with others. Then there's the problem of keeping them alphabetical. The only real difficulty I see is when a monster spans over more than one page and the stat block is separate from the description and requires a page flip. Even then, I'd prefer that over an artificially large book if it only meant flipping pages for a handful of creatures.